The arbitration exception (exceptio compromissi) has a procedural character and constitutes a question of jurisdiction, therefore it must be raised, on pain of forfeiture, in the first defensive pleading of the defendant party. Arbitral jurisdiction cannot be assimilated to functional jurisdiction so as to justify its ex officio detection by the court, being founded solely on the parties' will.
The presence of an arbitration clause does not prevent requesting and obtaining from ordinary courts a payment order for debts arising from contract, whilst preserving the respondent's right to raise arbitral jurisdiction in opposition proceedings, with consequent necessity for the opposition court to revoke the payment order and direct the parties before a sole arbitrator or arbitral tribunal.
In the presence of an arbitration clause concerning all disputes arising from contract excluding summary or conservatory proceedings, opposition proceedings to a payment order, not being capable of inclusion within such proceedings, remain subject to arbitration.